Catalyst system

ABSTRACT

A propylene polymerization catalyst is formed by incorporation into a catalytic mixture, comprising a transition metal compound and an organoaluminum compound, effective amounts of hexavalent sulfur mineral acid or anhydride whereby the amount of n-hexane-soluble polymeric product is decreased.

BACKGROUND OF THE INVENTION

This invention relates to propylene polymerization catalysts andparticularly relates to catalyst systems which produce commerciallyacceptable levels of low molecular weight and, especially, substantiallyamorphous polymers as determined by the amount of polymerized productwhich is soluble in n-hexane at room temperature ("Hexane Solubles").

The polymerization of propylene to normally-solid, substantiallycrystalline polymers using heterogeneous catalysts comprising transitionmetal halides and aluminum alkyls now is well known in the art. However,there is a continuing need in the industry for complete catalyst systemswhich produce a high yield, as measured by the grams of crystallineproduct per gram of transition metal halide consumed, while producing aminimum amount of Hexane Solubles. In a slurry polymerization processwhich uses a hydrocarbon solvent, such as n-hexane, amorphous and lowmolecular weight polymer accumulates in the solvent which necessitatesextensive solvent purification procedures. Since the economic value ofsuch n-hexane-soluble polymer is lower than normally-solid,substantially crystalline product, the overall process becomes lessefficient as the amount of Hexane Solubles increase. A commerciallydesirable catalyst system would produce low amounts of Hexane Solubleswhile maintaining reasonable yields. The product produced using suchcatalyst system desirably has acceptable odor and environmentalqualities. Also desirable is a low concentration of residual titanium.

In a solventless, liquid-phase bulk polymerization or in a gas phaseprocess, the production of polymers which contain more than about 2% ofHexane Solubles requires a separate extraction procedure to producecommercially acceptable products and makes these inherently efficientprocesses uneconomical. Therefore, polymerization processes whichproduce low amounts of Hexane Solubles while not adversely affectingpolymerization yield are in demand.

Various catalyst modifiers in addition to transition metal halides andaluminum alkyls have been disclosed to minimize Hexane Solubles inalpha-olefin polymerizations. Such modifiers include aromatic oraliphatic amines, esters, amides, phosphites, phosphines, phosphineoxides, aldehydes, tetraorganosilyl compounds such as tetraalkyl-,tetraaryl- and tetraalkoxysilanes, sterically hindered cyclic amines,amine N-oxides and organotin sulfides. Known catalyst modifiers includethe combination of hydrogen sulfide, sulfur dioxide or bis(tributyl)tinsulfide with an aromatic amine or amine oxide such as lutidine,collidine (2,4,6-trimethylpyridine) and lutidine-N-oxide. Specificcatalyst systems including such combinations of modifiers are describedin U.S. Pat. Nos. 3,950,268 and 4,072,809 both incorporated by referenceherein. Although such modifiers do tend to decrease Hexane Solubles,they or their reaction products may produce undesirable odor or othereffects in polymeric product.

Molecular weights of alpha-olefin polymers have been controlled byaddition of "hydrogen active" compounds such as mineral acids to theolefin stream or directly to the polymerization reaction (U.S. Pat. No.3,161,628). U.S. Pat. No. 2,971,950 discloses adding anhydrous hydrogenhalide or alkyl halide to an alpha-olefin polymerization to controlmolecular weight. U.S. Pat. No. 3,271,381 uses 0.5 to 3 gram-equivalentsof a strong acid per gram-atom of titanium to control molecular weightof polyolefins.

The use of halogen acids, e.g., HCl or HBr, to treat catalyst supportsis taught in U.S. Pat. Nos. 3,658,722 and 3,888,789. Hydrogen chloridegas has been incorporated in alpha-olefin polymerization to produceelastomers (U.S. Pat. No. 3,563,964) and to change polymerization to acationic process (U.S. Pat. No. 3,692,712). U.S. Pat. No. 3,275,569teaches reducing titanium tetrahalide with aluminum in the presence of ahydrogen halide to form a polymerization catalyst component, while U.S.Pat. No. 2,256,264 teaches a polymerization catalyst system from ahalogenated metal of groups IVa, Va, or VIa (e.g. TiCl₄), aluminumchloride, hydrogen chloride and powdered aluminum. U.S. Pat. No.3,121,064 teaches regenerating a titanium halide catalyst component withdry halogen chloride. Sulfur dioxide and sulfur trioxide have beendisclosed to treat an olefin polymerization catalyst componentconsisting of a titanium or vanadium compound supported on a metal oxideor hydroxide (U.S. Pat. No. 4,027,088 and British Pat. No. 1,492,549).

Certain mineral and organic acids and anhydrides have been used inolefin polymerization systems which do not employ an organoaluminum-transition metal compound catalyst to form crystallinepolymers. References to such systems are made in U.S. Pat. Nos.3,426,007, 3,476,731, 3,497,488, U.S. Pat. No. Re. 29,504, U.S. Pat.Nos. 3,676,523, 3,686,351, 3,850,897, 3,896,087, and 4,029,866.

Carboxylic acids have been added to ethylene polymerization to reducedeposition of polymer on reactor walls (U.S. Pat. No. 3,082,198). Alkalimetal salts of inorganic oxyacids have been used in an olefinpolymerization catalyst comprising an aluminum sesquihalide and atransition metal halide (U.S. Pat. No. 3,400,084). Acid and base ionexchange resins have been used in olefin polymerization systems toproduce crystalline polymer (U.S. Pat. No. 3,595,849).

An object of this invention is to produce catalyst modifiers whichdecrease Hexane Solubles while maintaining reasonable polymerizationactivity. A further object of this invention is to produce a polymericproduct having acceptable odor. Other objects are described herein.

SUMMARY OF THE DISCLOSURE

A propylene polymerization catalyst is formed by incorporating into acatalytic mixture comprising a transition metal compound and an organoaluminum compound, effective amounts of hexavalent sulfur mineral acidor anhydride whereby the amount of n-hexane-soluble polymeric product isdecreased.

BRIEF DESCRIPTION OF THE INVENTION

Advantages of this invention include catalyst system which produces acommercially acceptable amount of Hexane Solubles polymer whilemaintaining reasonable catalytic activity. Further, catalyst modifiersof this invention generally do not introduce unacceptable levelsodor-forming compounds nor known compounds which may be environmentallydetrimental. Since the modifiers of this invention are mineral acids oranhydrides, possibly harmful complex organic compounds are not added tothe polymerization system.

The modifiers useful in this invention are hexavalent sulfur mineralacids or anhydrides. Examples of such compounds are sulfuric acid,oleum, halosulfonic acids such as chlorosulfonic acid and fluorosulfonicacid, and sulfur trioxide. Sulfur trioxide (SO₃) is the anhydride of ahexavalent sulfur mineral acid, i.e. sulfuric acid. Sulfuric acid usefulin this invention preferably is concentrated aqueous sulfuric acidincorporating about 96% H₂ SO₄. Fuming sulfuric acid typically is oleumcontaining about 27-33 wt.% free SO₃. Less concentrated sulfuric acid isuseful, although as the acid concentration decreases, excess watershould be removed, for example, by adding more organoaluminum compound.More concentrated sulfuric acid, also useful, is manufactured bycombining sulfur trioxide and water. A combination of equal molalquantities of SO₃ and water results in 100% sulfuric acid. If more thanan equal molal amount of SO₃ is added, the resulting material typicallyis called oleum, the strength of which usually is expressed as apercentage of free SO₃ in the acid. Properties of sulfuric acid andoleum are given below:

    ______________________________________                                                                           Freezing                                               Equivalent  Sp. Gr.    Point                                      Strength    H.sub.2 SO.sub.4 (%)                                                                      (15.6° C.)                                                                        (°C.)                               ______________________________________                                        60° Be                                                                             77.67       1.706      -12                                        66° Be                                                                             93.19       1.835      -35                                        96%         96          1.843      -14                                        98%         98          1.844      -2                                         99%         99          1.842      4                                          100%        100         1.839      11                                         10% oleum   102.25      1.880      0                                          20% oleum   104.50      1.915      -5                                         25% oleum   105.62      1.934      9                                          30% oleum   106.75      1.952      19                                         60% oleum   114.63      1.992      2                                          ______________________________________                                    

Examples of hexavalent sulfur mineral acids are discussed inKirk-Othmer, Encyclopedia of Chemical Technology, Second Edition, inVol. 19, pages 242-249 and 441-482, Vol. 9, pages 676-681, and Vol. 5,pages 357-363, all such pages are incorporated by reference herein.

The exact amount of the modifiers useful in this invention variesdepending upon the specific modifier, the precise make-up of the othercatalyst components, and the polymerization conditions. Typicallyeffective amounts range from a molar ratio to the transition metalcompound of about 0.005 to 1 to about 0.7 to 1 and preferably about 0.01to 1 to about 0.5 to 1. If sulfuric acid, fuming sulfuric acid or sulfurtrioxide is used, the preferable amount is present in a molar ratio tothe transition metal compound of about 0.01 to 1 to about 0.5 to 1. Ifchlorosulfonic acid is used, the preferable amount is present in a molarratio to the transition metal compound of about 0.01 to 1 to about 0.1to 1. The concentration of modifiers must be sufficient to show adecrease in Hexane Solubles. At reasonably low levels of modifiers, theyield of polymeric product is not seriously affected. However, at higherlevels of modifier the yield of product tends to decrease. An optimumlevel of modifier will produce both acceptable yields of Hexane Solublesand polymeric product.

For the purpose of determining Hexane Solubles, the "n-hexane" used is amixture of substantially C-6 hydrocarbons containing about 85-88 wt. %normal hexane.

Although not preferred, modifiers of this invention can be utilized inconjunction with effective catalyst coadditives such as alkyl silicates,orthosilicate esters, esters, Lewis bases such as phosphines,phosphites, phosphates, phosphine oxides, aromatic amines, amine oxides,tertiary aliphatic amines and ethers or an organometallic chalcogenidesuch as bis(trialkyl)tin sulfide. These additional additives can bepresent in minor amounts ranging from about one-tenth to 30 mol percentand preferably about 1 to 20 mol percent of the transition metal halidein the catalyst system. Two or more suitable hexavalent sulfur mineralacids can be combined and used in this invention. In addition, thehexavalent sulfur mineral acids or anhydrides can be mixed with othercompatible mineral acids for use in this invention.

The catalyst system described in this invention contains (a) anorganoaluminum compound and (b) a transition metal compound in additionto minor amounts of other additives.

Useful organoaluminum compounds include trialkylaluminum,dialkylaluminum halides, mixtures of trialkylaluminum withdialkylaluminum halides and mixtures of trialkylaluminum withalkylaluminum dihalides. Also catalytic effective amounts of mixtures oftrialkylaluminums and dialkylaluminum halides can be used in conjunctionwith alkyl aluminum dihalides. Useful halides include bromides andchlorides and useful alkyl radicals contain from two to about six carbonatoms. The preferable halide is chloride and the preferable alkylradical is ethyl. Diethylaluminum chloride (DEAC) is most preferable. Ina trialkylaluminum-dialkylaluminum halide mixture, the preferred amountof trialkylaluminum is about 20 to 50 mol percent. In atrialkylaluminum-alkylaluminum dihalide mixture, the preferred amount oftrialkylaluminum is about 30 to 70 mol percent and most preferably about40 to 60 mol percent.

The transition metal compounds useful as a component in the catalystsystem of this invention are compounds of transition metals of GroupsIVB, VB and VIB of the Periodic Table. Preferably, the transition metalcompound is a halide of titanium, vanadium, chromium or zirconium. Mostpreferably, titanium trichloride and especially activated titaniumtrichloride is used. Titanium trichloride can be activated to a highdegree of polymerization activity by chemical and physical means. Oneuseful activated titanium trichloride has an approximate stoichiometricformula of TiCl₃.1/3AlCl₃ and has been comminuted. Further, titaniumtrichloride can be activated by forming adducts with Lewis bases such asethers or by supporting the titanium trichloride on a catalyticallyinert substance such as a metal oxide or salt. One suitable titaniumtrichloride is described in U.S. Pat. No. 3,984,350 incorporated byreference herein.

The molar ratio of transition metal halide to organoaluminum compound ina catalyst system can range from about one-tenth to about 10, typicallyis about 1 to 3 and preferably is about 2. The amount of catalyst in apolymerization depends on the reactor size and type and on the amountand type of olefin monomer and is known to the skilled artisan.

Preferably, a catalyst system package is made prior to introduction ofsuch package into a polymerization reactor. Catalyst components can bemixed together in any order, typically using an inert hydrocarbon or themonomer as a suitable medium, although preferably the modifiers firstare added to an inert hydrocarbon solution of the organoaluminumcompound. Preferably, the catalyst modifiers of this invention are addedslowly while mixing to a solution of organoaluminum compound in an inerthydrocarbon. Such resulting mixture is added to a suspension oftransition metal compound in an inert hydrocarbon. After complete mixingthe resulting catalyst package can be introduced into a polymerizationreactor.

Since the catalyst systems used in this invention are sensitive tooxygen and moisture, suitable precautions should be taken duringcatalyst preparation, transfer and use.

The polymerization process of this invention can be practiced atpressures ranging from about atmospheric to about 20,000 p.s.i.g. andpreferably from about 30 to 1000 p.s.i.g.

The polymerization time depends on the process used. In batch processesthe polymerization contact time usually is about one-half to severalhours and typically is one to four hours in autoclave processes. In acontinuous process, contact time in the polymerization zone iscontrolled as required and typically ranges from about one-half toseveral hours. Since in this type of process unreacted monomercontinuously can be recycled into the polymerization zone, the contacttime can be shorter than in a batch process.

The liquid organic solvents used in the slurry polymerization techniqueinclude aliphatic alkanes and cycloalkanes such as pentane, hexane,heptane or cyclohexane; a hydrogenated aromatic compound such astetrahydronaphthalene or decahydronaphthalene; a high molecular weightliquid paraffin or mixtures of paraffins which are liquid at thereaction temperature; an aromatic hydrocarbon such as benzene, tolueneor xylene; or a haloaromatic compound such as chlorobenzene,chloronaphthalene or o-dichlorobenzene. Other suitable solvents includeethylbenzene, isopropylbenzene, ethyltoluene, n-propylbenzene,diethylbenzenes, mono and di-alkylnaphthalenes, n-pentane, n-octane,isooctane and methyl cyclohexane. Preferably, liquid hydrocarbons areused; most preferably, n-hexane is the polymerization medium. Althoughthe nature of the solvent can be varied considerably, the solvent shouldbe liquid under the reaction conditions and should be relatively inert.Advantageously, the solvent used can be purified prior to use bydistillation, by reaction with an aluminum alkyl, or by adsorption withmolecular sieves.

The polymerization temperature depends upon the specific catalyst systemused and can range from below about 0° C. to about 120° C. However, attemperatures below about 0° C. the polymerization rate slows and reactorresidence times become unreasonably long, while at temperatures aboveabout 120° C. the polymerization rate is too high which results inexcessive amounts of n-hexane-soluble products. Preferably, thetemperature ranges from about 2° C. to about 95° C. and most preferablyfrom about 50° C. to about 80° C.

After polymerization catalyst residues contained in the polymericproduct can be deactivated by conventional methods such as washing withmethanol, water and caustic. Washing polymer with water and caustic isbelieved to transform sulfur compounds, contained in residual catalystmodified with sulfuric acid, to sulfate ion.

This invention is useful in polymerizing propylene to a normally solid,substantially crystalline polymer, although propylene also can bepolymerized with minor amounts up to about 30 wt.% of ethylene or othercopolymerizable alpha-olefins containing up to 10 carbon atoms to formrandom, pure-block, terminal block and multisegment copolymers.

The normally-solid propylene polymers prepared according to thisinvention have molecular weights ranging from about 50,000 to 5,000,000and typically range from about 200,000 to 2,000,000. The molecularweights of such propylene polymers can be controlled by methods known tothe art, such as by polymerizing in the presence of hydrogen in anamount determined by melt flow rate or by the molecular weightdistribution desired.

This invention is demonstrated but not limited by the followingExamples.

EXAMPLES I-VI

A series of propylene polymerizations were performed using varioushexavalent sulfur mineral acids as catalyst modifiers. In addition,control runs were performed without modifiers of this invention.

Modified catalyst was prepared in a nitrogen-purged dry box by adding ameasured amount of modifier dropwise with stirring to a portion ofdiethylaluminum chloride (25 wt.% in hexane). This mixture then wasadded dropwise with stirring to a suspension of titanium trichloride inhexane. The quantities were measured such that two moles of DEAC wereadded to one mole of TiCl₃.

Two milliliters of the resulting modified DEAC-TiCl₃ mixture werediluted with 200 milliliters of dry n-hexane in a 450 milliliterpressure bottle which was sealed, placed in a water bath maintained at160° F. Propylene was introduced into the bottle and a pressure of 40p.s.i.g. maintained for two hours while stirring magnetically. After twohours the bottle was cooled, uncapped and the contents filtered. A 10%aliquot was taken from the filtrate and evaporated. The remaining solidmaterial was weighed to determine the amount of Hexane Solubles. Thefiltered solid polypropylene was vacuum dried and weighed. Results areshown in Table I.

                                      TABLE I                                     __________________________________________________________________________                                  Yield                                                                             Hexane                                      Example                       (g/g of                                                                           Solubles                                    (Run)                                                                              Catalyst (Molar Ratio)   TiCl.sub.3)                                                                       (Wt. %)                                     __________________________________________________________________________    (A)  DEAC/AA TiCl.sub.3.sup.1 133 3.41                                             (2/1)                                                                    (B)  DEAC/AA TiCl.sub.3 /BTS/Collidine                                                                      119 1.50                                             (2/1/0.02/0.02)                                                          I    DEAC/AA TiCl.sub.3 /Sulfuric Acid (96%)                                                                107 2.0                                              (2/1/0.09)                                                               II   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3.sup.2                                                  100 1.8                                              (2/1/0.05)                                                               III  DEAC/AA TiCl.sub.3 /SO.sub.3                                                                           93.5                                                                              1.5                                              (2/1/0.01)                                                               IV   DEAC/AA TiCl.sub.3 /Sulfuric Acid (96%)/Nitric Acid                                                    100 2.9                                              (2/1/0.02/0.02)                                                          (C)  DEAC/ABC-TiCl.sub.3.sup.3                                                                              335 1.02                                             (2/1)                                                                    (D)  DEAC/ABC-TiCl.sub.3 /BTS/Collidine                                                                     312.5                                                                             0.76                                             (2/1/0.02/0.02)                                                          V    DEAC/ABC-TiCl.sub.3 /Sulfuric Acid (96%)                                      (2/1/0.04)               273.8                                                                             0.8                                         VI   DEAC/ABC-TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                       286.3                                                                             0.71                                             (2/1/0.04)                                                               __________________________________________________________________________     .sup.1 AA TiCl.sub.3 -Stauffer Chemical Company Type 1.1                      .sup.2 H.sub.2 SO.sub.4 --SO.sub.3 -Fuming sulfuric acid-oleum (27-33 wt.     % free SO.sub.3)                                                              .sup.3 ABC-TiCl.sub.3 (prepared according to U.S. Pat. No. 3,984,350)    

EXAMPLES VII-XVII

A series of propylene polymerizations using hexavalent sulfur mineralacids as a catalyst modifier were performed in a one-gallon autoclave.Modified catalysts were made using the procedure described in ExamplesI-VI. For polymerization, a one-gallon, glass-lined, stirred,nitrogen-flashed autoclave was charged with 1550 milliliters of dryn-hexane and heated to about 140° F. To this autoclave, catalyst slurrycontaining 0.4 grams of TiCl₃ was added followed by 5 to 6 addedp.s.i.g. of hydrogen and 1830 milliliters of liquid propylene with thetemperature maintained at about 142° F. and the pressure at about 210p.s.i.g. The temperature was increased to about 160° F. and a constantpressure of about 240 p.s.i.g. was maintained by continued addition ofpropylene. After polymerizing four hours, the autoclave was vented andpolymer slurry was removed. Residual catalyst was deactivated by adding100 milliliters of methanol and stirring for 30 minutes at 160° F.

The amount of Extractables was determined by measuring the loss inweight of a sample of dry, ground polymer after being extracted inboiling n-hexane for six hours. Results are shown in Table II.

                                      TABLE II                                    __________________________________________________________________________                           Yield                                                                         (g/g                                                                              Hexane                                                                             Extract-                                                                           Bulk                                     Example                of  Solubles                                                                           ables                                                                              Density                                  (Run)                                                                              Catalyst (Molar Ratio)                                                                          TiCl.sub.3)                                                                       (%)  (%)  (lb/ft.sup.3)                            __________________________________________________________________________    (E)  DEAC/AA TiCl.sub.3 (1)                                                                          1558                                                                              12.6 (2)  24.8                                          (2/1)                                                                    (F)  DEAC/AA TiCl.sub.3 /H.sub.2 S/Collidine                                                         1480                                                                              5.8  1.3  25.1                                          (2/1/0.02/0.02)                                                          VII  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                      1228                                                                              5.7  (2)  25.1                                          (2/1/0.3)                                                                VIII DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3 (3)                                             1568                                                                              4.2  1.2  24.7                                          (2/1/0.15)                                                               IX   DEAC/AA TiCl.sub.3 /SO.sub.3                                                                    1430                                                                              3.4  1.1  25.5                                          (2/1/0.15)                                                               (G)  DEAC/AA TiCl.sub.3 /BTS/Collidine (4)                                                           1342                                                                              6.2  (2)  (2)                                           (2/1/0.02/0.02)                                                          X    DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                      1682                                                                              5.9  (2)  (2)                                           (2/1/0.2)                                                                XI   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                      1380                                                                              5.6  (2)  (2)                                           (2/1/0.3)                                                                XII  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                      1668                                                                              6.2  (2)  (2)                                           (2.4/1/0.2)                                                              (H)  DEAC/AA TiCl.sub.3 /H.sub.2 S/Collidine (5)                                                      800                                                                              6.1  1.2  26.0                                          (2.1/0.02/0.02)                                                          XIII DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub. 4 (96%) (5)                                                 1180                                                                              5.8  1.4  27.6                                          (2/1/0.15)                                                               XIV  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3 (5)                                              900                                                                              5.0  1.4  27.2                                          (2/1/0.15)                                                               XV   DEAC/AA TiCl.sub.3 /CSA (6)                                                                     1608                                                                              6.9  1.8  25.3                                          (2/1/0.03)                                                               XVI  DEAC/AA TiCl.sub.3 /CSA                                                                         1512                                                                              4.1  1.1  25.3                                          (2/1/0.06)                                                               XVII DEAC/AA TiCl.sub.3 /CSA                                                                         1242                                                                              4.2  1.1  22.5                                          (2/1/0.09)                                                               __________________________________________________________________________      (1) AA TiCl.sub.3 -Stauffer Chemicals, Type 1.1                               (2) Not measured                                                              (3) H.sub.2 SO.sub.4 --SO.sub.3 -fuming sulfuric acid-oleum(27-33 wt. %      free SO.sub.3)                                                                 (4) BTS - Bis-(tributyl)tin sulfide                                           (5) Polymerization time - 2 hours                                             (6) CSA - Chlorosulfonic acid                                           

EXAMPLES XVIII-XX

A series of propylene polymerizations were performed in a 30-gallonreactor using a catalyst modified with various hexavalent sulfur mineralacids.

A catalyst package was prepared by adding a measured amount of modifierdropwise to DEAC (25% in hexane) in a nitrogen-purged drybox withstirring. Then the DEAC-modifier mixture was added dropwise to asuspension of 15.16 grams of TiCl₃ while stirring. For polymerization,after 51.3 pounds of hexane, 30.8 pounds of propylene and 6 to 7 addedp.s.i.g. of hydrogen were charged to a 30-gallon autoclave vessel, theprepared catalyst package was introduced. The vessel was maintained atabout 155° F. while stirring at 425-450 rpm. Constant pressure of about260 p.s.i.g. was maintained by continuous addition of propylene. Afterthe polymerization time, the vessel was partially vented and thecontents transferred into a separate tank in which the remainingcatalyst was deactivated with methanol (10 vol.% in water) and sodiumhydroxide (5 wt.% in water), after which the polypropylene product waswashed with water. After liquids were decanted, the remaining solidproduct was neutralized, filtered and tumble dried. Results are shown inTable III.

Batches using similar preparative techniques were combined andproperties of such combined and stabilized materials are shown in TableIV.

An odor panel, consisting of at least six individual, evaluatedunidentified pellets produced from the polymers that were produced inExamples XVIII-XX and in Run J.

One day before an odor evaluation, pellets were placed in wide-mouth,half-gallon, glass jars fitted with aluminum foil-lined caps which hadbeen thoroughly cleaned and flushed with hot air. The sniffing techniquewas to pick up a sample jar in both hands, shake it twice, loosen thecap but not remove it from the jar, hold mouth end of the jar up to theface approximately one to two inches from the nose, lift the cap fromthe jar and quickly take three to four sniffs of the jar air space andthen replace the tighten the cap. Panelists breathed deeply through thenose for about 30 seconds before sniffing again. In order to minimizeany fluctuation in odor sensitivity, the panel only met at one timeduring a day.

Odor intensity was rated according to the following relative scale:

0--no detectable odor

1--barely detectable (Several sniffs are necessary to decide if an odoris present.)

2--detectable (Little effort is required to detect odor on opening ofjar.)

3--noticeable (Implies an inability to escape attention.)

4--prominent (More striking than 3 and seems to overwhelm sense ofsmell.)

5--strong and lingering (Causes aftertaste in mouth and nose needslonger to recover.)

The quality of odor was described in any term familiar to the panelists.At the end of each evaluation, the panel discussed odor intensity andquality and attempted to reach a consensus.

The panel consensus was that all samples tested in a first evaluationexhibited a noticeable odor with an intensity of 3 on a scale of 0 to 5,although there were differences in odor quality. Pellets made from Run Jhad a collidine, musty, burnt odor while samples made from ExamplesXVIII-XX had sour, sulfury, acidic and burnt qualities. Example XX had avery strong hexane odor apparently caused by incompletedevolatilization. After all samples were heated over a weekend at 150°F. under a nitrogen purge, the odor panel reevaluated these strippedsamples with a consensus that the odor intensity was barely detectablein Run J (1 on a scale of 0-5) and detectable for Examples XVIII-XX (2on a scale of 0-5). The odor qualities for Run J were waxy, musty andburnt and for Examples XVIII-XX were sulfury, onion and sour. Unstrippedpellets were molded into cups. The odor panel found the cup made frompolymer produced in Run J to have odor with noticeable intensity and atypical slurry, musty quality. Cups made from polymers of ExamplesXVIII-XX had a noticeable burnt odor but not musty. After sitting atroom temperatures of a day in sealed bags the odor of samples of ExampleXVIII-XX decreased in intensity to barely detectable and had a lemonycharacter but not burnt. The sample of Run J retained its mustycharacter. Two members of the panel speculated that because the rapiddissipation of the burnt odor, such phenomenon resulted from the moldingoperation and resided on the surface of the cups. The panel's summarywas that the odor exhibited in polymer made in Examples XVIII-XX hadanother odor quality which is less objectionable in quality to thatnoticed in polymer made in Run J.

                                      TABLE III                                   __________________________________________________________________________                                 Yield                                                                         (g/g                                                                              Hexane                                                                             Melt Flow                               Example                      of  Solubles                                                                           Rate                                    (Run) Catalyst (Molar Ratio) TiCl.sub.3)                                                                       (wt. %)                                                                            (g/10 min.)                             __________________________________________________________________________    (H)   DEAC/AA TiCl.sub.3.sup. 1                                                                            1000                                                                              21   4.3                                           (2/1)                                                                   (J(a))                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 S/Collidine                                                              1006                                                                              4.8  5.1                                           (2/1/0.02/0.02)                                                         (J(b))                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 S/Collidine                                                              1003                                                                              4.7  2.4                                           (2/1/0.02/0.02)                                                         XVIIIX(a)                                                                           DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                            944                                                                              5.5  5.7                                           (2/1/0.3)                                                               XVIII(b)                                                                            DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                            942                                                                              --   3.9                                           (2/1/0.3)                                                               XIX(a)                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3 (SO.sub.3 -30 wt.             %)                     1009                                                                              3.5  1.8                                           (2/1/0.17)                                                              XIX(b)                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3 (SO.sub.3 -30 wt.             %)                     1001                                                                              3.5  2.0                                           (2/1/0.1)                                                               XX(a) DEAC/AA TiCl.sub.3 /SO.sub.3                                                                         1000                                                                              3.4  2.0                                           (2/1/0.1)                                                               XX(b) DEAC/AA TiCl.sub.3 /SO.sub.3                                                                         1000                                                                              3.1  3.5                                           (2/1/0.1)                                                               __________________________________________________________________________     .sup.1 AA TiCl.sub.3 - Stauffer Chemical Company - Type 1.1.             

                  TABLE IV                                                        ______________________________________                                        Example                                                                       (Run)           (J)     XVIII   XIX   XX                                      ______________________________________                                        Melt Flow Rate                                                                (g/10 min. at 230° C.)                                                                 2.9     4.6     2.9   3.0                                     Hexane Extractables                                                           (%)             1.5     2.2     1.5   1.7                                     Volatiles                                                                     (%)             0.25    0.40    0.23  0.48                                    Density (g/cc)  0.9073  0.9056  0.9063                                                                              0.9057                                  Heat Deflection                                                               Temp (°F.)                                                                             232     226     238   230                                     Flexural Modulus                                                              (10.sup.3 psi)  238     211     226   215                                     Izod Impact                                                                   (ft-lb/in)      0.52    0.55    0.63  0.79                                    Tensile Impact                                                                (ft-lb/in.sup.2)                                                                              34.1    29.4    36.6  29.3                                    Gardner Impact                                                                (in-lbs)        6.33    4.20    3.57  5.80                                    Yield Tensile                                                                 Strength (psi)  5510    5310    5500  5310                                    Ultimate Tensile                                                              Strength (psi)  3450    3070    3210  3390                                    Elongation at                                                                 Yield (%)       8.67    9.43    8.23  9.05                                    Elongation at                                                                 Break (%)       32      65      35.2  48                                      Ash (%)         0.042   0.029   0.034 0.029                                   Yellowness Index                                                                              6.27    3.08    5.03  2.83                                    Relative                                                                      Brightness      68.5    69.7    68.4  69.9                                    Oven life-50 mil plaques.sup.1                                                 300° F., hours                                                                        165     129     165   93                                       320° F., hours                                                                        21      25      25    29                                      Elemental                                                                     Analysis (ppm)                                                                X-ray Fluorescence                                                            Ca              52      54      49    59                                      Cl              23      22      30    51                                      P               33      35      35    51                                      S               1       5       7     4                                       Ti              52      11      9     11                                      Atomic Absorption                                                             Al              54      42      47    44                                      Ti              57      12      9     11                                      Fe              7       1       6     1                                       Na              35      30      28    25                                      Ca              47      48      46    51                                      ______________________________________                                         .sup.1 Failure determined when 10% of surface shows crazing after exposur     in circulating air oven.                                                 

EXAMPLES XXI-LIII

A series of propylene polymerizations were performed using varioushexavalent sulfur mineral acids as a catalyst modifier. Catalystpreparation and polymerizations were performed in the manner describedin Examples I-VI. In catalyst preparation, either 0.2 gram of AA TiCl₃or 0.08 gram of ABC-TiCl₃ was used. Results are shown in Table V.

                                      TABLE V                                     __________________________________________________________________________                             Yield                                                                             Hexane                                           Example                  (g/g of                                                                           Solubles                                         (Run) Catalyst (Molar Ratio)                                                                           TiCl.sub.3)                                                                       (%)                                              __________________________________________________________________________    (K)   DEAC/AA TiCl.sub.3.sup. 1                                                                        99.5                                                                              3.54                                                   (2/1)                                                                   (M)   DEAC/AA TiCl.sub.3 /BTS/Collidine.sup.2                                                          94.0                                                                              1.52                                                   (2/1/0.02/0.02)                                                         XXI   DEAC/AA TiCl.sub.3 /SO.sub.3 /Collidine                                                          82.5                                                                              1.46                                                   (2/1/0.01/0.02)                                                         XXII  DEAC/AA TiCl.sub.3 /SO.sub.3                                                                     93.5                                                                              1.59                                                   (2/1/0.01)                                                              XXIII DEAC/AA TiCl.sub.3 /SO.sub.3                                                                     80  1.66                                                   (2/1/0.01)                                                              XXIV  DEAC/AA TiCl.sub.3 /SO.sub.3 /MB.sup.3                                                           94.0                                                                              1.61                                                   (2/1/0.01/0.03)                                                         XXV   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3.sup.4                                            102 2.03                                                   (2/1/0.03)                                                              XXVI  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  99.5                                                                              1.86                                                   (2/1/0.05)                                                              XXVII DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  100.5                                                                             1.87                                                   (2/1/0.08)                                                              XXVIII                                                                              DEAC/AA TiCl.sub.3 /CSA.sup.5                                                                    111.5                                                                             2.23                                                   (2/1/0.03)                                                              XXIX  DEAC/AA TiCl.sub.3 /CSA                                                                          100.0                                                                             1.88                                                   (2/1/0.06)                                                              XXX   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                       114.5                                                                             2.72                                                   (2/1/0.06)                                                              XXXI  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  105.5                                                                             2.45                                                   (2/1/0.06)                                                              XXXII DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)/MB                                                    128.5                                                                             1.97                                                   (2/1/0.06/0.045)                                                        XXXIII                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3 /MB                                              104 2.84                                                   (2/1/0.06/0.045)                                                        XXXIV DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  110.5                                                                             2.66                                                   (2/1/0.1)                                                               XXXV  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  100.5                                                                             2.80                                                   (2/1/0.1)                                                               (N)   DEAC/AA TiCl.sub.3 127.5                                                                             3.40                                                   (2/1)                                                                   XXXVI DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  120 2.36                                                   (2/1/0.06)                                                              XXXVII                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  108 1.88                                                   (2/1/0.12)                                                              XXXVIII                                                                             DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  91  1.69                                                   (2/1/0.24)                                                              XXXIX DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  71  1.82                                                   (2/1/0.3)                                                               XL    DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                  80  1.62                                                   (2/1/0.42)                                                              (O)   DEAC/ABC-TiCl.sub.3.sup.6                                                                        335 1.02                                                   (2/1)                                                                   XLI   DEAC/ABC-TiCl.sub.3 H.sub.2 SO.sub.4 --SO.sub.3                                                  288.8                                                                             0.59                                                   (2/1/0.18)                                                              XLII  DEAC/ABC-TiCl.sub.3 /H.sub.2 SO.sub.4 (96%)                                                      273.8                                                                             0.83                                                   (2/1/0.24)                                                              XLIII DEAC/ABC-TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3 /MB                                             283.8                                                                             0.39                                                   (2/1/0.18/0.05)                                                         (P)   DEAC/ABC-TiCl.sub.3                                                                              331.3                                                                             1.46                                                   (2/1)                                                                   XLIV  DEAC/ABC-TiCl.sub.3 SO.sub.3                                                                     307.5                                                                             0.55                                                   (2/1/0.1)                                                               XLV   DEAC/ABC-TiCl.sub.3 /H.sub.2 SO.sub.4 --SO.sub.3                                                 286.3                                                                             0.62                                                   (2/1/0.1)                                                               XLVI  DEAC/ABC-TiCl.sub.3 /H.sub. 2 SO.sub.4 (96%)                                                     262.5                                                                             0.88                                                   (2/1/0.1)                                                               (Q)   DEAC/ABC-TiCl.sub.3                                                                              525.0                                                                             1.94                                                   (2/1)                                                                   (R)   DEAC/ABC-TiCl.sub.3 /BTS/Collidine                                                               476.3                                                                             0.65                                                   (2/1/0.02/0.02)                                                         XLVII DEAC/ABC-TiCl.sub.3 /CSA/Collidine                                                               444.0                                                                             0.52                                                   (2/1/0.02/0.028)                                                        XLVIII                                                                              DEAC/ABC-TiCl.sub.3 /CSA                                                                         448.8                                                                             0.69                                                   (2/1/0.028)                                                             XLIX  DEAC/ABC-TiCl.sub.3 /CSA                                                                         423.8                                                                             0.62                                                   (2/1/0.056)                                                             L     DEAC/ABC-TiCl.sub.3 /CSA                                                                         390.0                                                                             0.59                                                   (2/1/0.084)                                                             (S)   DEAC/ABC-TiCl.sub.3                                                                              455.0                                                                             1.56                                                   (2/1)                                                                   LI    DEAC/ABC-TiCl.sub.3 H.sub.2 SO.sub.4 (100%)                                                      411.3                                                                             0.73                                                   (2/1/0.1)                                                               LII   DEAC/ABC-TiCl.sub.3 /H.sub.2 SO.sub.4 (100%)                                                     375.0                                                                             0.70                                                   (2/1/0.2)                                                               LIII  DEAC/ABC-TiCl.sub.3 /H.sub.2 SO.sub.4 (100%)                                                     342.5                                                                             0.74                                                   (2/1/0.3)                                                               __________________________________________________________________________     .sup.1 AA TiCl.sub.3 - Stauffer Chemicals Type 1.1                            .sup.2 BTS -- Bis-(tributyl)tin sulfide                                       .sup.3 MB -- Methyl benzoate                                                  .sup.4 H.sub.2 SO.sub.4 --SO.sub.3 - Fuming sulfuric acid-oleum (27-33 wt     % free SO.sub.3)                                                              .sup.5 CSA -- Chlorosulfonic acid                                             .sup.6 ABC-TiCl.sub.3 (prepared according to U.S. Pat. No. 3,984,350)    

EXAMPLES LIV-LXII

In a manner described in Examples VII-XVII, a series of polymerizationswere performed in a one-gallon autoclave using either AA TiCl₃ or TohoTiCl₃ with 96% H₂ SO₄ modifier. In each case 0.4 gram of TiCl₃ was used.Results are shown in Table VI.

                                      Table VI                                    __________________________________________________________________________                        Yield                                                                             Hexane      Bulk                                      Example             (g/g                                                                              Solubles                                                                           Extractables                                                                         Density                                   (Run)                                                                              Catalyst (Molar Ratio)                                                                       TiCl.sub.3)                                                                       (%)  (%)    (lb/ft.sup.3)                             __________________________________________________________________________    LIV  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4.sup.1                                                   1685                                                                              5.7  1.6    25.3                                           (2/1/0.2)                                                                LV   DEC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                          1620                                                                              6.2  1.4    24.7                                           (2/1/0.2)                                                                LVI  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                         1381                                                                              5.6  1.3    25.3                                           (2/1/0.3)                                                                LVII DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                         1646                                                                              6.2  1.7    25.8                                           (2.4/1/0.2)                                                              LVIII                                                                              DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                         1382                                                                              6.8  2.0    25.3                                           (2.6/1/0.3)                                                              LIX  DEAC/Toho-TiCl.sub.3 /H.sub.2 SO.sub.4.sup.2                                                 1672                                                                              1.5  1.7    26.2                                           (2/1/0.2)                                                                LX   DEAC/Toho-TiCl.sub.3 /H.sub.2 SO.sub.4                                                       1776                                                                              1.4  1.1    23.4                                           (2/1/0.3)                                                                LXI  DEAC/Toho-TiCl.sub.3 /H.sub.2 SO.sub.4                                                       1803                                                                              1.8  1.7    27.0                                           (2.4/1/0.2)                                                              LXII DEAC/Toho-TiCl.sub.3 /H.sub.2 SO.sub.4                                                       1834                                                                              1.6  1.6    23.6                                           (2.6/1/0.3)                                                              __________________________________________________________________________     .sup.1 AA TiCl.sub.3 - Stauffer Chemical Company Type 1.1                     .sup.2 Toho TiCl.sub.3 - Toho Titanium Company (TAC) S-13B               

EXAMPLES LXIII-LXVIX

A series of propylene polymerizations were performed using 96% sulfuricacid as a catalyst modifier. Catalyst preparation and polymerizationswere performed in the manner described in Examples I-VI. Results areshown in Table VII.

EXAMPLE LXX

A series of propylene polymerizations were performed according to theprocedures described in Examples I-VI using sulfamic acid as thehexavalent sulfur mineral acid modifier together with a control runusing no modifiers. All runs used DEAC and TiCl₃ in a molar ratio of 2to 1. The control run had a yield (grams of polymer per gram of TiCl₃)of 125.5 and Hexane Solubles of 4.3 wt.%. At a sulfamic acid molar ratioto TiCl₃ of 0.03, 0.06 and 0.1 the yields were 122.5, 118 and 121 withHexane Solubles of 4.1, 4.1 and 4.2 wt.% respectively. At a sulfamicacid molar ratio of 0.2 the yield was 122.5 and Hexane Solubles was 3.6wt.%.

The preceding Examples show that this invention is useful inpolymerizations which produce acceptable levels of Hexane Solubles whilemaintaining catalyst activity. Further, the polymer produceddemonstrates overall acceptable odor characteristics.

                  Table VII                                                       ______________________________________                                                                Yield   Hexane                                        Example                 (g/g of Solubles                                      (Run)  Catalyst (Molar Ratio)                                                                         TiCl.sub.3)                                                                           (%)                                           ______________________________________                                        (T)    DEAC/AA TiCl.sub.3                                                                              108.5  4.1                                                  (2/1)                                                                  (U)    DEAC/AA TiCl.sub.3                                                                             108     3.95                                                 (2/1)                                                                  LXIII  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           103.5   3.88                                                 (2/1/0.01)                                                             LXIV   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           104     3.94                                                 (2/1/0.05)                                                             LXV    DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           101.5   3.38                                                 (2/1/0.1)                                                              LXVI   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           96      2.96                                                 (2/1/0.2)                                                              LXVII  DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           97      2.81                                                 (2/1/0.3)                                                              LXVIII DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           90.5    2.63                                                 (2/1/0.5)                                                              LXIX   DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           82      2.73                                                 (2/1/0.7)                                                              (W)    DEAC/AA TiCl.sub.3 /H.sub.2 SO.sub.4                                                           43      4.15                                                 (2/1/1.0)                                                              ______________________________________                                    

I claim:
 1. A catalyst composition for the polymerization of propyleneor mixtures of propylene and copolymerizable alpha-olefins, whichproduces low amounts of n-hexane-soluble polymer, comprising a titaniumtrihalide; an organoaluminum compound selected from the group consistingof dialkyl aluminum halide, trialkyl aluminum, a mixture thereof, and amixture of trialkyl aluminum with alkyl aluminum dihalide; and ahexavalent sulfur mineral acid or anhydride in a molar ratio to titaniumtrihalide from about 0.005 to 1 to about 0.7 to
 1. 2. The catalystcomposition of claim 1 wherein the transition metal compound is titaniumtrichloride.
 3. The catalyst composition of claim 1 wherein thehexavalent sulfur mineral acid or anhydride is sulfuric acid, oleum,halosulfonic acid or sulfur trioxide.
 4. The catalyst composition ofclaim 1 wherein the hexavalent sulfur mineral acid is sulfuric acid. 5.The catalyst composition of claim 1 wherein the hexavalent mineral acidis oleum.
 6. The catalyst composition of claim 1 wherein the hexavalentmineral acid is chlorosulfonic acid.
 7. The catalyst composition ofclaim 1 wherein the hexavalent mineral anhydride is sulfur trioxide. 8.The catalyst composition of claim 3 wherein the titanium trihalide istitanium trichloride and the organoaluminum compound is diethylaluminumchloride, triethylaluminum, a mixture thereof or a mixture oftriethylaluminum with ethylaluminum dichloride.
 9. The catalystcomposition of claim 3 wherein the molar ratio of hexavalent mineralacid to titanium trihalide is about 0.01 to 1 to about 0.7 to
 1. 10. Thecatalyst composition of claim 4 wherein the molar ratio of sulfuric acidto titanium trihalide is about 0.01 to 1 to about 0.5 to
 1. 11. Thecatalyst composition of claim 5 wherein the molar ratio of oleum totitanium trihalide is about 0.01 to 1 to about 0.5 to
 1. 12. Thecatalyst composition of claim 7 wherein the molar ratio of sulfurtrioxide to titanium trihalide is about 0.01 to 1 to about 0.5 to
 1. 13.The catalyst composition of claim 6 wherein the molar ratio ofchlorosulfonic acid to titanium trihalide is about 0.01 to 1 to about0.1 to
 1. 14. The catalyst composition of claim 3 wherein the titaniumtrihalide is titanium trichloride and the organoaluminum compound isdiethylaluminum chloride.
 15. A process for forming a catalystcomposition for the polymerization of propylene or mixtures of propyleneand copolymerizable alpha-olefins, which produces low amounts ofn-hexane-soluble polymer, comprising mixing in a suitable medium atitanium trihalide; an organoaluminum compound selected from the groupconsisting of dialkyl aluminum halide, trialkyl aluminum, mixturesthereof, and a mixture of trialkyl aluminum with alkyl aluminumdihalide; and a hexavalent sulfur mineral acid or anhydride in a molarratio to titanium trihalide from about 0.005 to 1 to about 0.7 to
 1. 16.The process of claim 15 wherein the hexavalent sulfur mineral acid isadded to a solution of organoaluminum compound in an inert hydrocarbonthen the resulting mixture is added to a mixture of titanium trihalidein an inert hydrocarbon.
 17. The process of claim 15 wherein thetitanium trihalide is titanium trichloride and the organoaluminumcompound is diethyl-aluminum chloride.
 18. The process of claim 16wherein the inert hydrocarbon is n-hexane.
 19. The process of claim 15wherein the hexavalent mineral acid is sulfuric acid.
 20. The process ofclaim 15 wherein the hexavalent mineral acid is oleum.
 21. The processof claim 15 wherein the hexavalent mineral anhydride is sulfur trioxide.22. The process of claim 15 wherein the hexavalent mineral acid ischlorosulfonic acid.